Radio receiving apparatus



April 1929- M. .1, LOVE 1,708,767

RADIO RECEIVING APPARATUS Filed Aug.28, 1925 2 Sheets-Sheet l ,flJLav WITNE:

April 1929 M. J. LOVE 1,708,767

RADIO RECEIVING APPARATUS Filed Aug.28, 1925 2 Sheets-Sheet 2 Patented Apr. 9, 1929.

UNITED; STATES PATENT GFFICE.

MARTIN JGHESOH LOVE, OF ASELAND, QBEGOE.

EADIO RECEZVING APPARATUS.

A nl'ieation filed Au ust 2-8, 1925. Serial No. 53162.

inductances together with variable capacitanees all of which will coact, when properly adjusted, to accomplish the desired results.

Another object is to provice a circuit which will involve the use of only a comparatively small number of instruments which may be easily connected and adjusted without requiring any excessive degree of skill so that the operation may be carried out by a person of ordinary intelligence.

/Vith the above and other objects and advantages in View, the invention consists in the details of construction and arrangement of parts to be hereinafter more fully described and claimed, and illustrated in the accompanying drawings in which:

Figure 1 is a view of a radio set constructed in accordance with the invention, this view showing in elevation, the instruments mounted on the rear of the panel and also showing in top plan, the instruments mounted on the base,

Figure 2 is a diagram of the circuit. Initially, it might be mentioned that it is the peak values that should be the same on any wave length in the reception of radio broadcasting.

As a consequence, the energy content of the static surge with the secondary will be less thanthat of the signals, a condition which makes it possible to utilize filtering means for the removal or trapping out of these interfering conditions. 7

In carrying out the invention I preferably make use of the apparatus disclosed in the drawings wherein the letter X designates a panel and B the base board. Mounted on the panel I have shown a variable condenser V of suitable capacity connected with the antenna terminal or binding post 1 this condenser being connected with one terminal of an inductance L The wave band is lowered to a low meter or low frequency through an inductance coil L which is in close coupling with an inductance D". In actual practice the inductance L is preferably a coil of copper tubing which may conveniently have five which coil is located the coil L which passes through the entire length. It is at this point that the interterence is trapped out. The coil turns of a diameter, say, of three inches, in

L is connected to coil L At this point the circuit is split, a portion of the antenna cur rent passing through the coil L and through the condenser V, another portion of the current passing through the coils and L and being grounded through the variable switch S and also the switch S enabling the operator to cut that part of the coil L to obtain the proper values of inductance through a by-pass from switch S to coilL The other I side ot the coil L is grounded to the binding post or terminal I in sets designed for use in connection with a loop antenna. This side of the coil L connects to the negative side of the pole of the magnet Mto prevent the strays from passing through the magnet.

The coi L is preferably shunted by a variable condenser V of suitable capacity. The positive side of this part of the inductance circuit is connected with the stator plates of the variable condenser V the rotary plates of which are connected to the inside of the coil L and onto the binding post I for the antenna. The negative side of the coil L is connected to thebinding post 1'" provided for connection with a B battery. The rotary plates of the condenser V are also connected to thepositive side of the coil U, the inside of which connects to the positive side of the magnetic coil L The inside of coil L connects to the radio frequency side of the crys tal detector or rectifier C. The audio frequency terminal of the crystal connects to the inside of the magnetic coil L so that current will pass through this coil to the binding post I and to the coil L The positive side of this circuit is split between the coil L and the coil L passing through a potentiometer P back to inside of the coil L and outside of coil L is connected to the rotary plates of the variable condenser V The stationary plates of this condenser are connected to the inside end of the coil L. In other words, this variable condenser V is shunted across the coil L and is used as a filter for this part of the circuit. I also provide a rheostat R which is connected to the binding post 1* where the negative terminal of the B battery is connected, and this rheostat is used to vary the resistance of the currentthrough the condenser D to the coil L and to condenser V the condenser D being of the fined type. The condenser D likewise of fixed type and of a higher capacity, is shunted vacrossthe potentiometer P and is used to smooth out the high frequencies in this part of the circuit. The fixed condenser D is shunted across the coils L cuit involving the use of a comparatively small number of instruments or auxiliary devices"for greatly improving reception over What is. ordinarily possible with the well known types of arrangements.

Attention is directed to the fact'that adequate means has 7 been provided not onlytor tuning purposes butl'also for trapping out and eliminating strays, static and in fact all undesired im pulses. It is believed that the construction,

operation and advantages will be readily apparent to one skilled in the art' Without furtlier explanation. V I V While I have shown and described a preferred embodiment of the invention, it should be understood that I reserve the right to make such changes in the form, construction and arrangement of parts as Will not depart from the spirit of the invention or the scope of the subjoined' claim.

Having thus described the invention, I

' claim:

In a radio receiver an input circuit including closely coupled tuned inductances, interference and static eliminating means comprising a horseshoe permanent magnet, inductances arranged between the pole pieces thereof andconnected in series With said input circuit, and a crystal detector connected in series With the last named inductances.

In testimony whereof I afiix my signature. MAR-TIN JOHNSON LOVE. 

